COVID-19, HIV, and Cryptococcal Meningitis Coinfections with Abnormal Laboratory Findings

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first introduced in China in 2019, and it has rapidly spread all around the world. Cryptococcus neoformans is the leading cause of fungal meningitis in human immunodeficiency virus- (HIV-) infected patients. A variety of laboratory tests have been introduced for rapid diagnosis of meningitis.

Here, we report a case of coinfection with COVID-19 and cryptococcal meningitis in a HIV-positive patient with abnormal laboratory findings. In this case, COVID-19 was positive by polymerase chain reaction (PCR) and computerized tomography (CT) scan diagnosis. Cryptococcal antigen testing of CSF was negative, whereas India ink staining and cerebrospinal fluid (CSF) culture confirmed the presence of C. neoformans.

Although the patient was in a critical stage of illness, serum and CSF levels of procalcitonin were abnormally low, within normal limits. On the other hand, although initial lumbar puncture had showed elevated protein level, the repeat CSFs presented remarkably reduced protein levels. Our findings indicate that despite COVID-19 infection, procalcitonin level may remain normal in HIV-associated cryptococcal meningitis, and findings of an apparently normal procalcitonin level should not exclude the possibility of infection. Also, antigen testing may present false-negative result, and it should not be the sole laboratory method for diagnosis of infectious meningitis. Consequently, CSF culture and staining is recommended, even when antigen testing of organism is negative and CSF profile is unremarkable.

Laboratory information should be combined with a good understanding of clinical manifestations of patient to determine if meningitis is present and confirmed COVID-19 should not ignore possibility of other infections for consideration.